[Organizers] what to do about a dancer with dementia

For the last three years, one of our older dancers has been declining with dementia--and her husband, not a good dancer himself, continues to bring her to our dances. Invariably, they create chaos on the dance floor. Most people on the board of my dance organization feel it's important to continue to include these dancers until such time that the husband decides it's time for them to stop coming. On the other hand, I'm concerned with the effect that they're having on other dancers. I've heard at least one dancer say that she considered not coming to a dance when she saw that this couple was there--and certainly this couple's presence is diminishing the dance experience of many of the dancers who've come to our events for the high level of dancing that we were able to deliver in the past. Has anyone else wrestled with this sort of problem? If yes, what did you do (or not do) about it? Thanks, Katy Heine